51 lines
2.1 KiB
Ruby
51 lines
2.1 KiB
Ruby
module DanbooruImageResizer
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# Taken from ArgyllCMS 2.0.0 (see also: https://ninedegreesbelow.com/photography/srgb-profile-comparison.html)
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SRGB_PROFILE = "#{Rails.root}/config/sRGB.icm"
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# http://jcupitt.github.io/libvips/API/current/libvips-resample.html#vips-thumbnail
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THUMBNAIL_OPTIONS = { size: :down, linear: false, auto_rotate: false, export_profile: SRGB_PROFILE }
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# http://jcupitt.github.io/libvips/API/current/VipsForeignSave.html#vips-jpegsave
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JPEG_OPTIONS = { background: 255, strip: true, interlace: true, optimize_coding: true }
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# XXX libvips-8.4 on Debian doesn't support the `Vips::Image.thumbnail` method.
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# On 8.4 we have to shell out to vipsthumbnail instead. Remove when Debian supports 8.5.
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def self.resize(file, width, height, quality = 90)
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if Vips.at_least_libvips?(8, 5)
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resize_ruby(file, width, height, quality)
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else
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resize_shell(file, width, height, quality)
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end
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end
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# https://github.com/jcupitt/libvips/wiki/HOWTO----Image-shrinking
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# http://jcupitt.github.io/libvips/API/current/Using-vipsthumbnail.md.html
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def self.resize_ruby(file, width, height, resize_quality)
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output_file = Tempfile.new
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resized_image = Vips::Image.thumbnail(file.path, width, height: height, **THUMBNAIL_OPTIONS)
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resized_image.jpegsave(output_file.path, Q: resize_quality, **JPEG_OPTIONS)
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output_file
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end
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def self.resize_shell(file, width, height, quality)
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output_file = Tempfile.new(["resize", ".jpg"])
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# --size=WxH will upscale if the image is smaller than the target size.
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# Fix the target size so that it's not bigger than the image.
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image = Vips::Image.new_from_file(file.path)
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target_width = [image.width, width].min
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target_height = [image.height, height].min
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arguments = [
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file.path,
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"--eprofile=#{SRGB_PROFILE}",
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"--size=#{target_width}x#{target_height}",
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"--format=#{output_file.path}[Q=#{quality},background=255,strip,interlace,optimize_coding]"
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]
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success = system("vipsthumbnail", *arguments)
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raise RuntimeError, "vipsthumbnail failed (exit status: #{$?.exitstatus})" if !success
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output_file
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end
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end
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